Cellular and paging networks can send information to cellular telephones and pagers, respectively. To send information to a cellular telephone, a cellular network uses multiple radio-frequency channels for real-time voice or data transmission. The cellular network can also use a store-and-forward messaging service known as Short-Message Service to forward messages from one channel of a cell site. To send information to a pager, a paging network uses a single, shared radio-frequency channel and a store-and-forward system to schedule message delivery over the shared channel. Two-way pagers typically operate on the 901-902, 930-931, and 940-941 MHz range.
Although both cellular telephones and pagers can be used to transmit information, cellular telephones are much more versatile. With a cellular telephone, a user can input voice information by speaking into the telephone and can input data information by using the telephone keypad to type alpha-numeric characters. To transmit a message from a pager, a user is often limited to manipulating navigation keys (e.g., up and down arrows) or buttons corresponding to displayed soft keys to transmit built-in messages. Because the user's response is confined to built-in messages, two-way data communication using a pager is limited. Although some pagers have a keyboard to enable two-way data communication, some users may find the small keyboard difficult to use.
U.S. Pat. No. 5,751,693 to Dinkins offers one attempt to overcome the limitations associated with data transmission from a pager. A two-way messaging system is described at col. 7, lines 11-31 of the Dinkins patent in which a stylus is used to draw a message onto a data entry and display screen of a transmitting pager, and the drawn message is displayed on a receiving pager. The messaging system described in the Dinkins patent is an “ink-based” system—the written message or drawing transmitted to the receiving pager is essentially a duplicate of the message entered onto the screen of the transmitting pager. Because an image and not the content represented by the image is transmitted, ink-based systems are of limited use.
There is, therefore, a need for an improved pager with a touch-sensitive display screen and method for transmitting a message therefrom.